HK450 Build

[jmtyndall]

I've been down a transmitter, and can't maiden this thing yet, so I've been watching the finless bob videos, specifically related to the tail. I thought I had mine set up right, but I notice that if I set the arm on the tail to 90* to the boom, I have a ton of pitch that goes to the right. Do I need to do the grip flip mod, or do I just ignore that, leave it setup how I have it; 90* on the servo horn, 0* on the blades, ignore the slider to tail angle?


Edit to add obligatory picture. It seems like if I do the dremel mod, it will improve the condition slightly, but it won't end up giving me pitch in the right direction. If I do the grip flip, I will have pitch in the correct direction, but unequal throw in each direction. If it matters, I intend to fly heading hold.

[Meekrakkin]

I did the grip flip on mine... it flies good that way =)

[jmtyndall]

Did you have to do the dremel mod in conjuntion? Or move the servo ball to prevent binding?

[Meekrakkin]

Nah, just flipped the grips and changed the servo and gyro directions...

Just make sure your servo center is somewhere in the vicinity of center mechanically, set your endpoints in your FBL unit and it'll work fine =)

[Dyehard]

jmtyndall, from the picture, your HK has what would be condidered left tail rotor, since it would drive the nose to the left. A heli with a clockwise rotor needs less left tail rotor since torque is trying to turn the heli left anyway. To balance torque in a hover, you need to have few degrees of right tail rotor pitch in the blades, just the opposite of what yours has. Both mine and my sons HK 450s needed to have the tail grips flipped to get that necessary right tail rotor pitch with the tail lever centered. A real quick fix that works well.

[aerobob]

Originally Posted by jmtyndall

I've been down a transmitter, and can't maiden this thing yet, so I've been watching the finless bob videos, specifically related to the tail. I thought I had mine set up right, but I notice that if I set the arm on the tail to 90* to the boom, I have a ton of pitch that goes to the right. Do I need to do the grip flip mod, or do I just ignore that, leave it setup how I have it; 90* on the servo horn, 0* on the blades, ignore the slider to tail angle?


Edit to add obligatory picture. It seems like if I do the dremel mod, it will improve the condition slightly, but it won't end up giving me pitch in the right direction. If I do the grip flip, I will have pitch in the correct direction, but unequal throw in each direction. If it matters, I intend to fly heading hold.

+1 on the comment about the offset in tail rotor shown in picture. I set all of mine mechanically offset in "Rate" mode by sliding the servo on the boom, servo at center/neutral such that there is "some" amount of RIGHT offset (which is moving tail Left) so that is moving the leading edge of the upcoming tail blade TOWARD the boom, then locking the servo mounts.

Then, when using HH mode, the "mechanical" or dynamic neutral in the hover is established.

Admittedly, I am a relative noob on these finer points, but I have found this offset to be correct, and needed, even if using HH mode in a FBL controller.

[jmtyndall]

She has been maidened. Test spooled to 100% with a little negative pitch. Did fine, but seemed like a little tail left drift in rate mode. Put less static pitch in and spool up seemed fine. Lifted off and she wanted to drift left and piro cw. Got it under control and landed. Switched to avcs(heading hold) and tried again. Brought her up to hover in normal mode. Nice stable tail, no wag, no wander. It was too dark to try her in idle 1 or test for tail wag. Things I learned: she is SCARY, 40% expo is wayyyyy too soft for me. Going to turn it down to 20% expo and try again when there's more light, and after warming up on another bird

[jmtyndall]

A full maiden flight under it's belt! Hard to get time to fly with finals. Much better with the lower expo. Took her to idle 1, and tail authority is better at the higher speed. Rate mode, the tail drifts, lock it into HH and it's super steady. Piros are lightning fast, and no wag at this setting. I have been told to increase it until I get wag, then back it down. How many points do I increase it by at a time? I need to try a different Normal curve, because the one I have just isn't working out.

[xrayray]

Originally Posted by jmtyndall

I've been down a transmitter, and can't maiden this thing yet, so I've been watching the finless bob videos, specifically related to the tail. I thought I had mine set up right, but I notice that if I set the arm on the tail to 90* to the boom, I have a ton of pitch that goes to the right. Do I need to do the grip flip mod, or do I just ignore that, leave it setup how I have it; 90* on the servo horn, 0* on the blades, ignore the slider to tail angle?


Edit to add obligatory picture. It seems like if I do the dremel mod, it will improve the condition slightly, but it won't end up giving me pitch in the right direction. If I do the grip flip, I will have pitch in the correct direction, but unequal throw in each direction. If it matters, I intend to fly heading hold.

I have a small point to make about the tail mods. I agree with the finless videos about how the geometry is wrong on the tail and needs to be 90/90 for the most correct leverages. WELL align F-ed up but their direction is correct. It's up to you. If the tail were to blow out, would you want the servo to be pulling on the rod or pushing? If you run a carbon rod would you like it to push instead? The flimsy stock wire is intended to have pull on it or else it would start to bend between the guides on a very heavy tail load.

Also, the dremel mod increases positive pitch just because the hub is further out. It doesn't just help pitch at the other side. Yes if you have preload set it looks like you have way more negative pitch than positive (towards the tailcase), but if you can set left and right endpoints on your gyro then you're fine. This is why the dremel mod is a little better than flipping the grips.

[jmtyndall]

I think I get it now. I have 6 flights on the heli now. Flies well, plenty of power, but seems to be more powerful as it gets a few more flights on it. I think parts may be wearing in. I discovered my blades are too darn tight, going to loosen them up before my next flight. Also going to do the dremel mod. I have it completely dialed in and I'm thrilled with it. Almost considering upping the gains and roll rates.

[jmtyndall]

8 flights total and starting to have a lot of fun with this heli. More than my micros for sure, but it does make me nervous at times. I'm getting ready to order some crash parts in case I pile-drive this thing. I could order two new kits for the money of align replacement parts! But I'm probably going to get the align parts anyways.

A little confusion I'm having, I want to order linkage arms, which ones do I need? I think the metal parts are 20mm and 40mm, but the align links seem to be labeled with letters. Are there other align parts that aren't compatible with the HK kit? The torque tubes look way different, but seem to be the same diameter.

Any suggestions on parts to stock up on for a crash? I stressed the plastic on my servo tabs when I installed them, so I think they will probably break in a crash. With that said, I think I'm going to re-kit to the TGY 306G servos instead. Then if I strip a main gear I'll convert to an 11T/121 helical gear set-up